如何用有序数字替换列中的字符串？

Question

我有下表：

CityNamesZip5Plus4

===========================

Zip5    Plus4   CityName
===========================
36067   1500    Prattville
36067   1501    Prattville
36067   1502    Prattville

48085   3614    Troy
48085   3629    Troy
48085   3640    Troy
48085   3641    Troy

需要用从1开始的数字替换CityName

所以表看起来像这样：

CityNameNumberZip5Plus4

===========================

Zip5    Plus4   CityNameNumber
===========================
36067   1500    1
36067   1501    1
36067   1502    1

48085   3614    2
48085   3629    2
48085   3640    2
48085   3641    2

CityName-> CityNameNumber对应关系应在单独的表中：CityNamesNumbers

问题是如何生成CityNamesNumbers表并使用它 生成CityNameNumberZip5Plus4？

Answer 1

以下是用于BigQuery标准SQL

  

如何生成CityNamesNumbers表...

#standardSQL
CREATE OR REPLACE TABLE `project.dataset.CityNamesNumbers` AS
SELECT CityName, ROW_NUMBER() OVER() CityNameNumber 
FROM `project.dataset.CityNamesZip5Plus4`
GROUP BY CityName   

  

...并使用它生成CityNameNumberZip5Plus4？

#standardSQL
CREATE OR REPLACE TABLE `project.dataset.CityNameNumberZip5Plus4` AS
SELECT x.* EXCEPT(CityName), CityNameNumber
FROM `project.dataset.CityNamesZip5Plus4` x
JOIN `project.dataset.CityNamesNumbers` y
USING(CityName)